<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
  </head>
  <body>
    <script>
      //将简化字符转为html
      function convertChar(char) {
        let result = char.replace(/(.+)#(.+)\.(.+)/, '<$1 id="$2" class="$3"></$1>');
        return result;
      }
      console.log(convertChar("div#demo.demo"));
    </script>
  </body>
</html>
